Aquarium filter device

ABSTRACT

A method and system for the treatment of water in aquariums and the like utilizing aerobic action in which the water is withdrawn from the main body, exposed to the atmosphere, filtered and returned under pressure to the main body from below the same, the preferred embodiment of apparatus comprising a filter structure disposed exteriorly of the aquarium water and supplied therefrom, with the filtered water being conducted to means disposed at the bottom of the aquarium constructed to support a layer of gravel or other discrete material thereon for dischare below such layer of discrete material, flowing therethrough under pressure.

United States Patent Appl. No.: 881,110

US. Cl ..2l0/l69 I 51 Int. Cl. ..E04h 3/20 58 -Field ofSearch..210/169-, 119/5 [56] V References Cited UNITED sTATEs PATENTS3,135,238 6/1964 Eyl ..119/5 3,516,544 6/1970 Sesholtz..- 2,783,8933/1957 Romanoff ..2l0/l69 x 3,485,373 12/1969 Powers ..2l0/169 3,490,4161/1970 Kelley et al. .12l0/l69 x White [4 1 Sept. 26, 1972 AQUARIUMFILTER DEVICE [72] inventor: Eugene B. White, Oak Park, Ill. PrimaryExaminer Reuben Friedman Assistant ExaminerT. A. Granger Asslgnee:xen'no Products 'P i Attorney-Hill, Sherman, Meroni, Gross & SimpsonPalos Helghts, lll. 221 Filed: Dec. 1, 1969 7] A STRA T A method andsystem for the treatment of water in aquariums and the like utilizingaerobic action in which the water is withdrawn from the main body,exposed to the atmosphere, filtered and returned under pressure to themain body from below the same, the preferred embodiment of apparatuscomprising a filter structure disposed exteriorly of the aquarium waterand supplied therefrom, with the filtered water being conducted to meansdisposed at the bottomof the aquarium constructed to support a layer ofgravel or other discrete material thereon for dis'chare below such layerof discrete material, flowing therethrough under pressure.

9 Claims, 9 Drawing Figures AQUARIUM FILTER DEVICE BACKGROUND or THEINVENTION The invention is directed to a water purification systemparticularly for application in aquariums and the like, and may employ afilter structure which may be very similar in construction to thatillustrate in my co-pending application, Ser. No. 805,274, filed on Mar.7, 1969 now US. Pat. No. 3,578,169, in particular utilizing areplaceable filtercartridge.

As pointed out in said application simple filter structures utilizingcharcoal or the like have been employed in small aquariums, for examplefrom 5 to 40 gallons capacity, the filter structure usually beingdisposed in the aquarium and the water circulated through the filter bymeans of a'small air pump operative to simultaneously provide aerationof the water. The filter system illustrated 'in said co-pendingapplication, as therein pointed out, whileinvolving an aerobic action,is designed to make use of anaerobic action in which debris'and organicmatter in the water settles to the bottom of the tank'intothe grave] orotherdiscrete material forming the. normal lower water level in thetank. A tray-like structurewas provided which upon was initiallydisposed a layer of discrete filter material which carried a layer ofthe usual aquarium gravel. In this construction, the-water was withdrawnfrom-below the tray-like structure and conducted to the filter fromwhich the-filtered water was discharged directly into the top of theaquarium tank. While some purification may have resulted from theoxidizing action on organic matter present as a resultof the oxygencontent within the water drawn through the aquarium gravel, whichoxidation would take place primarily at the interface between the gravellayer'and the layerof filter material therebelow, the primary action wasan aerobic in character, taking place in the filter bed, whereby organiccompounds were decomposed into gases with the contaminated water beingthen conducted to the filter and subsequently returned to the tank.

The present invention is directed to a method and apparatus utilizingbiofiltration (continuous recirculation at a high volume through ashallow filter bed) as the primary purification whereby settling andaccumulation of material carried in the water at the bottom of the tankis completely eliminated.

The present invention therefore is directed to an improved waterpurification system for aquariums and the like, utilizing aerobic actionand eliminating the disadvantages of prior aquarium filtering systems,including that illustrated in my co-pending application above referredto.

BRIEF SUMMARY OF THE INVENTION The invention is directed to a method ofpurifying water in aquariums and the like, and to apparatus forpracticing the same, in which the water containing the debris andmaterial to be removed therefrom is withdrawn from the main body of.water above the botsuitable means whereby the filtered water flows belowsuch gravel layer and is discharged upwardly therethrough, the rate ofreturn of the filtered water being adjustably selected to insureadequate water circulation within the main body. The rate of How is soselected that the water flow through the filter and thus returned to thetank is such that a volume of water equal to that of the tank may befiltered in a period of, for example, from 10 to 60 minutes. At highrates such as this, adequate aeration of the watertakes place fromexposure to the atmosphere occuring in the filter structure and theoxygen carrying filtered water thus is discharged at a high volume atthe bottom of the tank, with the gravel cooperating with the supportingstructure therefor to provide a very. effective distribution of thefiltered water throughout the tank bottom, whereby such water isdischarged in quantities sufficient to insure adequate purification ofthe water as well asthe rapid conduction of all debris and foreignmatter in the water into the external filter structure. I

As a result, any foreign material in the water at an particular instantis so small in quantity that it will not be apparent from visualobservation and the tank water will continuously maintain a clarity anddegree of purity that heretofore was not considered possible to achieve.Consequently, the tank is continuously kept in a clean condition and itis usually unnecessary to remove and clean the gravel or periodicallyrefill the tank, only adding make-up water to compensate forevaporation, etc.

The apparatus for practicing the invention, in the preferred formillustrated in the drawings, comprises an external filter structure,constructed with a removable and placeable filter cartridge, somewhatsimilar in general construction to that illustrated in my co-pendingapplication, with water being withdrawn from the tank at a locationabove the upper surface of the gravel and discharged into the filterstructure, from which it is withdrawn by means of a small pump andreturned, under pressure, to the bottom of the tank which is providedwith a gravel supporting structure constructed to receive the filteredwater and discharge the same upwardly through the gravel disposed onsuch structure. Thus, no specific filtering material is disposed at thebottom of the tank, with the aerobic purifying action taking placedirectly in the main body of the water and in the external filterstructure.

In the specific embodiment of the invention illustrated, the water iswithdrawn from the tank and discharged into the filter structure bymeans of a syphon action with the filtered water being discharged fromthe filter structure by means of a small electric pump which returns thewater, under pressure, to the tank.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantagesof the invention will be readily apparent from the following descriptionof a preferred embodiment taken in cona junction with the accompanyingdrawings, wherein like FIG. 1 is a perspective view of a filter systemembodying the present invention, illustrating its installation inaquarium tank, portions of the latter being broken away to illustratedetails of the invention;

FIG. 2 is a sectional view taken approximately on the line II-II of FIG.1;

FIG. 3 is a sectional view taken approximately on the line -IIIIII ofFIG. 1',

FIG. 4 is a sectional view through the filter structure takenapproximately, on the line IV-IV of FIG. 1;

FIG. 5 is a top plan view of a modified form of gravel supportingstructure;

FIG. 6 is a sectional view taken approximately on the line .VIVI of FIG.5;

FIG. 7 .is a sectional view taken approximately on the line VII-VII ofFIG. 5; M 7 FIG. 8 is a sectional view taken approximately on the lineVIII-VIII of FIG. 7; and

FIG. 9 is a perspective view of a modified form of filter structure.

DETAILED DESCRIPTION OF THE INVENTION For clarity the description willbe presented in three parts, the first being general and brieflycovering the basic components, the second being a detailed descriptionof the gravel supporting and water discharge structure, the thirdincluding details of the external filter structure and pump, and thefourth including details of modified constructions of the gravelsupporting structure and the external filter structure.

GENERAL CONSTRUCTION Referring to FIG. 1, the reference numeral 1indicates generally a gravel supporting structure, illustrated ascomprising two sections 2a and 2b which are adapted to be placed onthebottom of the aquarium tank, indicated generally by the numeral 3, withthe tray structures 2 being adapted to support a layer of gravel orother discrete material 4 in spaced relation above the tank bottom.

Disposed at the exterior of the rear wall 5 of the tank and supported onthe upper edge 6 thereof is a filter structure, indicated generallybythe numeral 7, comprising a hollow bodymember for casing 8 constructedto receive and support a filter cartridge 9. This cartridge 9 is in theform of a container which is open at the top, to form an inlet chamberat the top of the filter cartridge. Water passing through the filtercartridge 9 flows into a chamber or well 12 where it enters the inletopening 13 of a centrifugal pump 14 having a discharge outlet to whichis connected vertically extending conduit indicated generally by thenumeral 15.

The pump 14 is adapted to be actuated by a small electric motor 16, thedrive shaft of which is operatively connected to the impeller of thepump 14 by a magnetic coupling whereby the pump structure iseffectively,sealed with respect to the drive motor 16. The motor 16 and pump 14 may,for example, be of a commercially procurable construction and thedetails thereof form no part of the present invention. As clearlyillustrated in FIG. 1 the pump discharge conduit extends upwardly, beingreversely bent around the upper edge portion of the rear wall of thetank, as indicated at 17 and then downwardly as' indicated by thenumeral 18, with the lower end thereof being operatively connected tothe two tray structures 2a and 2b to supply filtered water to the spacebeneath the layer of gravel 4, as hereinafter described in detail.

The tank water to be filtered is supplied to the inlet chamber 11 of thefilter cartridge 9 by a pair of vertically extending conduits 19a and19b terminating at their upper ends in reversely bent portions with thefree ends thereof extending into the chamber 11, as clearly illustratedin FIG. 4.

The lower ends of the conduits 19a and 19b carry laterally extendingtubular members 21a and 21b respectively which are closed at their freeouter ends by cap members 22 and communicate at their opposite ends withthe respective conduits 19a and 19b. As clearly illustrated in FIG. 1the members 21a and 21b are provided with a plurality of transverselyextending slots 23 therein forming inlet passageways for the tank waterwhich may thus fiow into the conduits 19a and 19b and discharged intothe chamber 11 of the filter cartridge. The cap members 22 likewise maybe provided with slots 24 therein whereby the unfiltered water may bedrawn from adjacent the rear wall of the tank substantially throughoutthe lateral length of the latter.

As hereinafter described in detail the unfiltered water enters the slots23 and 24, rises upwardly in the conduits 19a and 19b into the filtercartridge, flowing downwardly through the latter and ultimatelydischarged into the chamber 12 from which it is withdrawn through thepump inlet 13 and discharged from the pump through the conduit 15 fromwhich it is discharged, under pressure, below the gravel layer 4,flowing upwardly through such gravel to the main body of water in thetank. 1

It will be apparent that as the conduits 19a and 19b have the freeinverted ends thereof, extending into the chamber 11, disposed below thenormal water level of the main body of water in the tank, as clearlyillustrated in FIG. 4, a syphon action results with the water level inthe chamber 11 tending to seek the same level as the main body of waterin thetank. It will be particularly appreciated that inasmuch as asyphon action is involved, there exists no danger of overflow as fillingof the chamber 11 will automatically cease when the level thereinreaches that of the water in the tank. Likewise, assuming that the waterlevel in the tank is maintained at its normal level as a result of theperiodic. addition of make-up water to compensate for evaporation, thesurface of the water in the tank will never fall to a level which resultin a breaking of the syphon action.

THE GRAVEL SUPPORTING STRUCTURE Referring to FIGS. 1 through 4, the traystructure 2a and 2b which are of identical general construction,differing only with respect to the position of the inlet for filteredwater, each comprise a shallow tray-like base member 25 having a bottomwall 25' and shallow peripheral walls 26, cooperable with partitionwalls27 to support a horizontally extending perforated top wall 28. The rearperipheral wall is extended upwardly as indicated in FIG. 2 to form therear wall 29 cooperable with a generally L-shaped member 31, which formsa front wall 32 and top wall 32' of a supply conduit or plenum sectionindicated generally by the numeral 33, the ends of which are closed byrespective end walls 34.

The components of such tray structures may, for example, be formed fromsuitable plastic materials with the respective components being suitablysecured by solvent'welding or other suitable means to form an.integralstructure.

Secured to each of the top walls 32' of the respective trays 2 is atubular fitting 35 which forms the inlet for filtered water into thetray structure, the fitting 35 on the tray 2a being disposed adjacentthe right end of the associated conduit 33 while the fitting 35 on thetray 26, is disposed adjacent the left end of the associated conduit 33.

As illustrated in FIG. 1 the lower end of the section 18 of the conduitis provided with a T connection 36 having two outlet ends 37a and 37bwhich are connected in fluid-tight relation to the respective fittings35 on the tray structures 2a and 2b.

It will be noted that the perforations 38 in the portion of the topwall'28 disposed opposite the wall 33 from inlet ports for the flow ofwater from the inlet fitting 35 to the respective spaces defined by theribs or partition walls 27 between the bottom 25 and top wall 28 wherebyan efficient distribution of filtered water to the entire area below thetop wall 28 is achieved. The expanded perforations 39 in the top wall 28are of a size to provide adequate water flow therethrough but aresmaller in area than the particles of discrete material, such as theusual aquarium gravel, whereby the top wall 28 will effectively retain alayer of discrete material thereon with the water discharged through theperforations 39 flowing upwardly between the interstices of the gravelor other discrete material thereon.

TI-IE EXTERNAL FILTER STRUCTURE Referring to FIGS. 1 and 4, the casingor body member 8 of the filter structure 7, suitably formed from plasticor other suitable material, comprises a generally vertically extendingfront wall 41 and a rear wall having offset portions 42a and 42bconnected by a rearwardly extending portion 43 whereby the frontto-reardimension of the clear water chamber 12 is greater than thecorresponding dimension of that portion of the housing receiving thefilter cartridge 9. Extending outwardly from the front wall 41, adjacentthe top edge thereof, is a horizontally extending wall 44, the freeouter edge of which extends downwardly to fonn a flange 45 adapted toengage the upper edge 6 of the aquarium tank and cooperable with aprojection 46 extending outwardly from the central portion of the wall41 to firmly retain the filter structure 7 on the upper edge of the tankas illustrated.

As previously mentioned the pump 14 and motor 16 are of standardconstructions, commercially available, and the details thereof form nopart of the present invention. In the construction illustrated in FIG.1, the pump 14 wouldnormally be at least partially formed out of thebottom wall of the chamber 12 with the impeller being separated by asolid wall to effectively seal the pump with respect to the motor. Thedrive shaft of the motor 16 and impellerof the pump 14 are provided withcooperable magnetic driving and driven coupling members disposed atopposite sides of the sealing wall but magnetically coupled to transmittorque from the drive shaft of the motor to the impeller of the pump.

THE FILTER CARTRIDGE The filter cartridge 9 is preferably constructed ofplastic or other suitable material and is of generally rectangular shapehaving side walls 47 and end walls 48 and 49, the lateral dimensions ofsuch walls being such that the walls 47 and end wall 49 are generallycomplemental to the adjacent side and end walls of the casing 8. The endwall 49 of the filter cartridge also forms the dividing wall between thefiltering chamber and the clear water chamber 12.

The bottom wall 51 of the cartridge is spaced upwardly from the bottomedges of the adjacent walls 47 and is provided with suitable openings 52therein to permit the flow of water out of the cartridge into thechamber between the bottom wall of the casing 8 and the bottom wall 51of the cartridge. The wall 48, as illustrated in FIG. 4 terminates atits lower edge adjacent the bottom wall 51 to provide a fluid dischargeport 53 through which the filtered water may flow to the chamber 12. Inaddition, a plurality of legs 54 may extend downwardly from the bottom51 to provide further support for the cartridge structure.

Referring to FIG. 1 it will be noted that interposed in the dischargeconduit 15 is a valve 55 which may, for example, be an ordinaryball-type valve adapted to be actuated by means of the handle 56 tocontrol the flow of filtered water from the pump 14, the valve being soconstructed that the water flow may be adjusted from free flow throughthe conduit 15 to a lesser amount, for a desired operation of thesystem.

Extending across the bottom wall 51 of the cartridge 9 is a thin sheet55 of a suitable material as for example a foam plastic which hasrelatively fine interconnected pores whereby water may readily passtherethrough but forming a retaining screen for a layer of relativelysmall particles of filter material 56. Disposed above the layer 56 is asimilar layer of relatively large filter particles 57 which may beseparated from the particles 56 by a dividing sheet 58 which may,comprise a sheet of the same foam plastic material as the sheet 55 anddisposed above the layer 57 is a similar retaining sheet 59 which may beof the same material as the sheets 55 and S8. The sheets 55, 58 and 59,in particular the sheet 59 may be suitably secured to the side walls 47and end wall 48, 49 whereby the particles of filter material 56 and 57are effectively retained in the cartridge.

In use the unfiltered water entering at the top of the cartridge passesprogressively through the relatively coarse filter material and thenthrough the relatively fine filter material 57 and 56 respectively a andis discharged into the chamber 53 at the bottom of the cartridge.

INSTALLATION AND OPERATION The system is readily installed by placingthe tray structures 2a and 2b on the bare bottom of the drained tank,the tray structures being suitably dimensioned to substantiallycompletely cover such bottom, as illustrated in FIG. 1. The filterstructure 7 is then positioned on the upper edge 6 of the rear wall ofthe tank as illustrated and the lower free end 18 of the dischargeconduit 15 is connected by means of the T fitting 36 to the respectivetray structures 2a and 2b, the ends 37a and 37b of the T portion 36being connected to the fittings 35 of the respective tray structure tooperatively connect the discharge side of the pump 14 to the interior ofthe respective tray structures.

The tray structures are then covered with a layer 4 of gravel or otherdiscrete material and the tank filled with water. The conduits 19a and19b and connected elements 21a and 21b are then immersed in the waterand permitted to fill completely. When the conduit 19a and member 21aare completely filled, the free upper end thereof is suitably plugged,as for example by means of a cork 61 having a handle 62 rigidlyconnected therewith, to seal such end, following which the conduit 19ais disposed in operative position as illustrated in FIG. 4 with the freeend extending downwardly into the'chamber 11 of the cartridge 9. Thecork'21 is then carefully withdrawn to permit the discharge of waterinto the cartridge. This operation is then repeated with respect to theconduit 19b and'associated member 21b. I

Following the addition of fish, plant life, and other objects into theaquariumthe electric motor 16 may be started and the valve 55 initiallyadjusted for maximum water flow. Filtered water will thus enter theinlet 13 of the pump and be discharged into the tray structures 2a and2b from which it will flow upwardly through the perforations 39 thereinand through the layer of gravel 4 into the main body of water. The valve55 is then adjusted to provide a suitable flow. In most cases the valve55 may be adjusted to provide maximum flow without disturbance to plantsand fish in the aquarium. The respective components are preferably soproportioned that with maximum water flow the water level in the chamber12 will be approximately one inch in height while the water level in thecartridge chamber 1 I will normally be at least approximately a quarterof an inch below the normal water level in the tank and at leastapproximately a quarter of an inch above the discharge end of theconduit 19a or 19 b.

Tests have shown that with a pump having a capacity, in operation underthe conditions described, of l gallons per minute, excellent results areobtainable in a I gallon tank with the valve 55 set to provide a flow ofone-half gaL/min, which would give complete turnover of the tank volumeevery 20 minutes. Consequently, in the absence of unusual circumstances,a 60 gallon tank could have a complete volume turnover in less than anhour, which would be a satisfactory rate for a tank this size to produceadequate biofiltration, and enabling the use of the system describedwith tanks of from to 60 gallons. The invention is, of course,applicable to larger tanks by the use of corresponding largercomponents.

It will be appreciated that the construction illustrated and describedinherently provides adequate safety features whereby there, is no dangerwhatsoever of an overfilling of the filter structure with overflowexterithe water level within the aquarium tank. This opera-.

tion likewise is completely independent of the pump whereby failure ofthe pump will have no material effect thereon. I

The construction of the tray structures 2a and 2b is such thatsubstantially uniform water flow is effected through the gravelthroughout the area thereof, creating a very effective water circulationin the tank. At the same time the capacity of the pump 14 issuch that acomplete change of tank water may be effected in short periods of timeas previously described.

MODIFIED TRAY STRUCTURE As previously mentioned, the tray structures 2aand 2b are preferably dimensioned to accommodate the average ten gallontank and while each tray section may be provided with its own inletfitting 35, as illustrated in FIG. 1, where more than 2 tray structuresare involved it may be desirable to provide additional means foroperatively connecting all tray structures with the discharge side ofthe pump 14.

FIGS. 5 through 8 illustrate a construction for use with three traystructures 20, 2d and 2e, illustrated in plan in FIG. 5. The traystructures 2d and 2e are generally identical in construction with theexception of the position of the water inlet thereto and likewise areidentical with the tray structures 2a.or 2b with the exception of theposition of the water inlet. With respect to the tray 2d, as illustratedin FIG. 6, the inlet is disposed at the right-hand end of the plenumconduit 33d and is formed by elimination of the adjacent end wall 34.The tray structure 2e is identical with the exception that instead ofproviding an open end at the right end of the plenum conduit 33d, theopen end is provided at the left end thereof.

The center tray section 20 is provided with a plenum conduit 33' whichreceives filtered water through the fitting 35 and distributes suchwater to the plenum conduits 33d and 336 as well as to a plenum conduit330 for the tray 20. The top wall of the conduits 33' and 330 are formedby the top wall 32'. of an angle member 31' while the front wall of theconduit 33c is formed by the depending wall 32 of such angle member. Avertical wall 63 of an angle member 64 forms the dividing partition wallbetween such conduits while the horizontally extending wall-63 thereofforms the bottom wall of the conduit 33'. To effect a connection betweenthe conduits 33d and 33e with the conduit 33' the opposite ends of theconduit 33' are provided with respective inverted U-shaped connectormembers 65, rigidly secured thereto and adapted to mate with theinterior surfaces of the open ends of the respective conduits 33d and33e. The conduit 330 is operatively connected to the supply conduit 33by an opening 66 in the verti cal wall of the angle member 64. Thusfiltered water entering the fitting 35 may flow into the conduit 33'from which it is conducted to the respective conduits 33d and 33e atopposite ends of the conduit 33' and to the conduit 33' and to theconduit 33c through the opening 63.

Obviously where more than three tray structures are employed theadditional tray structures may be supplied independently, as for exampleas illustrated in FIG. 1, or in some cases it may be desirable to employa plurality of tray sections constructed in the same manner as thesection 2c but omitting an inlet fitting 35 and connecting such traystructure intermediate two tray structures such as 2d and 2c.

MODIFIED FILTER STRUCTURE While the pump and motor assembly illustratedin FIG. 1 would appear to be suitable for most application's, suchconstruction does require a specially designed casing 8 to accommodatethe necessary magnetic coupling elements and in some cases it may bedeemed desirable to utilize a standard pump and motor assembly ascommercially procurable. Such a construction is illustrated in FIG. 9 inwhich the motor 16 and pump 14 are constructed as an integral unit whichis provided with a vertically extending inlet structure of generallytubular configuration having an enlarged perforated base portion whichis adapted to seat on the bottom of the casing 7 thus also forming asupport for the motor and pump assembly. In this construction thedischarge port is disposed at the opposite side of the pump structure,adjacent the motor 16' and is connected by a short conduit section tothe valve 55. The cartridge 9 and remaining structure is constructed inthe same manner as heretofore described with respect to the constructionof FIG. 1 and the general operation the filter structure of FIG. 9 isidentical with that of PK]. 1.

It will be appreciated from the above description that l have provided acomparatively simple yet highly efficient filter system for aquariumtanks and the like, utilizing aerobic action, in effect providing asewage disposal system for an aquarium tank having an efficiency whichinsures crystal water at all times as well as substantially eliminatingthe problem of periodic cleaning of the tank and in particular theremoval of waste matter accummulating in the gravel bed at the bottom ofthe tank. At the same time, the construction inherently provides safetyfeatures which eliminates any possibility of an overflow of waterexteriorly of the filter structure.

lclaim:

l. A filter system for aquariums and the like, utilizing aerobic action,comprising a filter structure adapted to be disposed exteriorly of thebody of water'in the bers, the surface of said tray-like structurehaving openings therein adapted to operatively communicate with the mainbody of water, with said openings being adapted to form the only wateroutlets for the respective chambers and disposed to provide relativelyuniform flow and distribution therefrom, said closed conduit meansoperatively connecting the filter outlet to the respective chambers forsupplying filtered water, in approximately equal volumes to therespective independent chambers under sufficient pressure to force thereturning water upwardly relatively uniformly into the main body ofwater with sufficient force to provide a flushing action with respect tosaid tray-like structure sufficient to flush debris and foreign materialinto the main body of water for ultimate withdrawal and accumulation insaid filter.

2. A filter system for aquariums and the like, utilizing aerobic action,comprising a filter structure adapted to be disposed exteriorly of thebody of water in the aquarium tank, said filter structure having acasing in which is disposed a filter body, the top of which is providedwith a water inlet and the bottom of which is provided with a wateroutlet, said casing being constructed to form a water chamber laterallyadjacent the filter body and communicating with the outlet in the bottomthereof, a tray-like structure, adapted to lie on the bottom of theaquarium. tank, said tray-like structure having side and opposed top andbottom walls forming at least one closed chamber, the upper surface ofsaid opposed top wall being adapted to support discrete material,partition means extending between said opposed top and bottom walls anddividing the chamber into a plurality of respective independentsections, the top walls of said sections defining substantially equalareas and having openings therein for providing a relatively uniformflow throughout the area of a section, with such openings being adaptedto form the only water outlets forthe respective section, closed conduitmeans forming a supply and distribution conduit extending adjacent anedge of the tray-like structure, said conduit having a water inletopening therein for the supply of filtered water, under pressure,thereto, said supply and distribution conduit adapted to havepassageways therein for the distribution of approximately equal volumesof water therefrom to each respective section, an impeller type waterpumphaving a suction side and a pressure side, the suction side of saidpump being operatively disposed in the lower portion of said waterchamber for withdrawing water therefrom, closed conduit means connectingthe pressure side of said pump to the water inlet opening of thedistribution conduit, means for actuating said pump, said filterstructure being constructed for external mounting on an aquarium withthe top of the filter body so disposed below the surface of the mainbody of water in the aquarium that the surface of such main bodyrepresents the maximum head of water above the filter body, syphon meansoperatively connecting the main body of water and the top of the filterbody, and manually adjustable valve means in said conduit at thepressure side of said pump for controlling the water volume dischargedby said pump, whereby such volume may be so adjusted that the waterlevel in said water chamber may be operatively maintained at a heightintermediate the pump inlet and the surface of the body of water abovesaid filter body to provide a pressure head thereacross, and at the sametime the water supplied to said tray-like structure will be forcedupwardly relatively uniformly into the main body of water withsufficient force to provide a flushing action with respect to saidtray-like structure, sufficient to flush debris and foreign materialinto the main body of water for ultimate withdrawal and accumulation insaid filter.

3. A filter system according to claim 2, wherein said supply conduit isdisposed adjacent the rear edge of said tray-like structure and abovethe latter, with the top wall thereof forming the bottom wall of suchconduit and openings in such wall forming the supply passageways for therespective sections thereof.

4. A filter system according to claim 3, wherein said tray-likestructure comprises an intermediate tray-like member and a similarmember at each side thereof forming three closed chambers, each beingdivided into respective independent sections, and each tray-like memberhaving a supply conduit, and a plenum conduit carried by saidintermediate tray member having a water inlet for connection to thepressure side of said pump, and having outlets therein communicatingwith the respective supply conduits of the individual tray members. r

5. A filter system according to claim 2, wherein said tray-likestructure comprises a plurality of individual tray-like memberscooperable to cover the entire bottom area of an aquarium tank, eachhaving a water inlet for the supply of filtered water thereto.

6. A filter system for aquariums and the like, utilizing aerobic action,comprising a filter structure adapted to be disposed exteriorly of thebody of water in the aquarium tank, said filter structure having a waterinlet adapted tooperatively communicate with water in the.

bonding on the main body of water defining substantially equal areas andhaving openings therein for providing a relatively uniform flowthroughout the area of a section, with such openings adapted to form theonly water outlets for the respective sections, closed conduit meansforming a supply and distribution conduit extending adjacent an edge ofthe tray-like structure, said supply and distribution conduit having awater inlet opening therein for the supply of filtered water, underpressure, thereto, said supply and distribution conduit adapted to havepassageways therein for the distribution of approximately equal volumesof water therefrom to each respective section, means operativelyconnecting said filter outlet to the water inlet conduit, for supplyingwater under pressure to said tray-like structure whereby such, waterwill be forced upwardly relatively uniformly into the main body of waterwith sufficient force to provide a flushing action with respect to saidtray-like structure, sufficient to flush debris and foreign materialinto the main body of water for ultimate withdrawal and accumulation insaid filtering step.

7. A filter system according to claim 6, wherein said supply conduit isdisposed adjacent the rear edge of said tray-like structure and abovethe latter, with the top wall thereof forming the bottom wall of suchconduit and openings in such wall forming the supply passageways for therespective sections thereof.

8. A filter system according to claim 7, wherein said tray-likestructure comprises an intermediate tray-like member and a similarmember at each side thereof forming three closed chambers, each beingdivided into respective independent sections, and each tray-like memberhaving a supply conduit, and a plenum conduit carried by saidintermeidate tray member having a water inlet for connection to saidwater supply means, and having outlets therein communicating .with therespective supply conduits of the individual tray membeg'A filter systemaccording to claim 7, wherein said tray-like structure comprises aplurality of individual tray-like members cooperable to cover the entirebottom area of an aquarium tank, each having a water inlet for thesupply of filtered water thereto.

1. A filter system for aquariums and the like, utilizing aerobic action,comprising a filter structure adapted to be disposed exteriorly of thebody of water in the aquarium tank, said filter structure having a waterinlet adapted to operatively communicate with water in the aquariumtank, and a water outlet, a pump adapted to deliver water underpressure, a tray-like structure, upon which discrete material may besupported, adapted to lie on the bottom of the aquarium tank, saidtray-like structure being adapted to form a plurality of independentclosed chambers at the bottom of the aquarium tank and beneath thesurface of said tray, closed conduit means in communication with saidpump and said plurality of independent closed chambers, the surface ofsaid tray-like structure having openings therein adapted to operativelycommunicate with the main body of water, with said openings beingadapted to form the only water outlets for the respective chambers anddisposed to provide relatively uniform flow and distribution therefrom,said closed conduit means operatively connecting the filter outlet tothe respective chambers for supplying filtered water, in approximatelyequal volumes to the respective independent chambers under sufficientpressure to force the returning water upwardly relatively uniformly intothe main body of water with sufficient force to provide a flushingaction with respect to said tray-like structure sufficient to flushdebris and foreign material into the main body of water for ultimatewithdrawal and accumulation in said filter.
 2. A filter system foraquariums and the like, utilizing aerobic action, comprising a filterstructure adapted to be disposed exteriorly of the body of water in theaquarium tank, said filter structure having a casing in which isdisposed a filter body, the top of which is provided with a water inletand the bottom of which is provided with a water outlet, said casingbeing constructed to form a water chamber laterally adjacent the filterbody and communicating with the outlet in the bottom thereof, atray-like structure, adapted to lie on the bottom of the aquarium tank,said tray-like structure having side and opposed top and bottom wallsforming at least one closed chamber, the upper surface of said opposedtop wall being adapted tO support discrete material, partition meansextending between said opposed top and bottom walls and dividing thechamber into a plurality of respective independent sections, the topwalls of said sections defining substantially equal areas and havingopenings therein for providing a relatively uniform flow throughout thearea of a section, with such openings being adapted to form the onlywater outlets for the respective section, closed conduit means forming asupply and distribution conduit extending adjacent an edge of thetray-like structure, said conduit having a water inlet opening thereinfor the supply of filtered water, under pressure, thereto, said supplyand distribution conduit adapted to have passageways therein for thedistribution of approximately equal volumes of water therefrom to eachrespective section, an impeller type water pump having a suction sideand a pressure side, the suction side of said pump being operativelydisposed in the lower portion of said water chamber for withdrawingwater therefrom, closed conduit means connecting the pressure side ofsaid pump to the water inlet opening of the distribution conduit, meansfor actuating said pump, said filter structure being constructed forexternal mounting on an aquarium with the top of the filter body sodisposed below the surface of the main body of water in the aquariumthat the surface of such main body represents the maximum head of waterabove the filter body, syphon means operatively connecting the main bodyof water and the top of the filter body, and manually adjustable valvemeans in said conduit at the pressure side of said pump for controllingthe water volume discharged by said pump, whereby such volume may be soadjusted that the water level in said water chamber may be operativelymaintained at a height intermediate the pump inlet and the surface ofthe body of water above said filter body to provide a pressure headthereacross, and at the same time the water supplied to said tray-likestructure will be forced upwardly relatively uniformly into the mainbody of water with sufficient force to provide a flushing action withrespect to said tray-like structure, sufficient to flush debris andforeign material into the main body of water for ultimate withdrawal andaccumulation in said filter.
 3. A filter system according to claim 2,wherein said supply conduit is disposed adjacent the rear edge of saidtray-like structure and above the latter, with the top wall thereofforming the bottom wall of such conduit and openings in such wallforming the supply passageways for the respective sections thereof.
 4. Afilter system according to claim 3, wherein said tray-like structurecomprises an intermediate tray-like member and a similar member at eachside thereof forming three closed chambers, each being divided intorespective independent sections, and each tray-like member having asupply conduit, and a plenum conduit carried by said intermediate traymember having a water inlet for connection to the pressure side of saidpump, and having outlets therein communicating with the respectivesupply conduits of the individual tray members.
 5. A filter systemaccording to claim 2, wherein said tray-like structure comprises aplurality of individual tray-like members cooperable to cover the entirebottom area of an aquarium tank, each having a water inlet for thesupply of filtered water thereto.
 6. A filter system for aquariums andthe like, utilizing aerobic action, comprising a filter structureadapted to be disposed exteriorly of the body of water in the aquariumtank, said filter structure having a water inlet adapted to operativelycommunicate with water in the aquarium tank and a water outlet, atray-like structure, adapted to lie on the bottom of the aquarium tank,said tray-like structure having side and opposed top and bottom wallsforming at least one closed chamber, the upper surface of said opposedtop wall being adapted to support discrete material, partition meansextending between Said opposed top and bottom walls and dividing thechamber into a plurality of respective independent sections, the wallsof said sections operatively bonding on the main body of water definingsubstantially equal areas and having openings therein for providing arelatively uniform flow throughout the area of a section, with suchopenings adapted to form the only water outlets for the respectivesections, closed conduit means forming a supply and distribution conduitextending adjacent an edge of the tray-like structure, said supply anddistribution conduit having a water inlet opening therein for the supplyof filtered water, under pressure, thereto, said supply and distributionconduit adapted to have passageways therein for the distribution ofapproximately equal volumes of water therefrom to each respectivesection, means operatively connecting said filter outlet to the waterinlet conduit, for supplying water under pressure to said tray-likestructure whereby such water will be forced upwardly relativelyuniformly into the main body of water with sufficient force to provide aflushing action with respect to said tray-like structure, sufficient toflush debris and foreign material into the main body of water forultimate withdrawal and accumulation in said filtering step.
 7. A filtersystem according to claim 6, wherein said supply conduit is disposedadjacent the rear edge of said tray-like structure and above the latter,with the top wall thereof forming the bottom wall of such conduit andopenings in such wall forming the supply passageways for the respectivesections thereof.
 8. A filter system according to claim 7, wherein saidtray-like structure comprises an intermediate tray-like member and asimilar member at each side thereof forming three closed chambers, eachbeing divided into respective independent sections, and each tray-likemember having a supply conduit, and a plenum conduit carried by saidintermeidate tray member having a water inlet for connection to saidwater supply means, and having outlets therein communicating with therespective supply conduits of the individual tray members.
 9. A filtersystem according to claim 7, wherein said tray-like structure comprisesa plurality of individual tray-like members cooperable to cover theentire bottom area of an aquarium tank, each having a water inlet forthe supply of filtered water thereto.